comes and goes

[fastracer]

fitted dump valve 2001 bug eye, in 3rd 4th around 5, 6000 revs its like somone has turned the fuel off then back on. only slightly could this be the dump valve or somthing else.hope you can help..

[Dyney]

Sounds a bit like boost/fuel cut.
Normally happens when your hard on the throttle and boost peeks past the set point. When it happens it feels like your going to headbutt the dash :haha:
Is yours this bad?
The ECU see's too much boost so cuts out momenteraly. It's a saftey feature :rolleyes:

[fastracer]

yes its when im hard on the throttle,its not as bad as head on dash. just like fuel starvation

[ScoobyDuck]

cuold be that fitting the new valve has cured a leaky old one, which now means its overboosting...

2 fixes -

1) change the small brass restrictor in the boost hosing
2) get a remap ;)

suppose you could always stick the old crappy one back on :p

[Dyney]

Does it do it at lower revs/speed ;)
If your hard on the throttle in a high gear from low revs?
Try a long pull in 3rd from about 2500 revs and hold it past 5/6000 revs :)

[WallyBazoom]

Agreed, most likely overboost but could also simply be a misfire.

Check/Clean and re-gap the spark plugs.

Might solve the problem.

[fastracer]

it doesnt do it at lower revs only in 3rd 4th 5th past 5000revs

[Dyney]

I know, but the way to test it is to start at low revs and pull in the same gear all the way through the revs so the boost hits it's highest pressure. If it does it then I suspect it is boost/fuel cut :)

If your up at C.J's soon get him to give me a call and you can take me for a spin to see for myself :)

[fastracer]

cheers dyney for looking at my car wed night. hope u will speak to your mate to see if he would check it out on his laptop:) :) :) :)

[Dyney]

Ahh yes, ScoobyDuck!
I don't think he can make the meet :(

Will have a chat to him and see what comes up ;)

[fastracer]

changed dump valve for standerd one seems to be a lot better.went up the gears alright only when came to a hill a27 nr asda towards brighton bit hesitant what do u think:confused: :confused:

[Dyney]

Need to get Scoobyduck and his laptop plugged in to it and see whats going on :)